Author Topic: 2T scooter - Ignition Help  (Read 634 times)

Scootsuper9

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2T scooter - Ignition Help
« on: September 19, 2024, 11:54:56 PM »
Hello,

I hoped to hit a larger audience than just my scoot, as I believe all Kymcos with a DC CDI operate the same. I have an 05 LC S9. Thing was fine I got it running for the first time on a while, and it had some downtime as I waited on parts to refresh.

Fast forward a few days and I got the carb back on after a rebuild, and other assorted goodies. I had to run the starter for a bit to prime the bowl (vacuum petcock) and that is where all went wrong. I am not sure if the voltage dropped too much and something fried, but my battery got pretty hot. I took it apart and assessed, all looked fine, fuses were good.

Rehooked battery, 12.8 V - now no spark.

See testing conditions and analysis below:
CDI: 4 wires in: 12.8V DC from battery - check. 1V AC from trigger coil when cranking - check. Ground is good, continuous, same for coil lead.

Coil looks good, resistance is on point. 0.1-0.2 ohms primary, about 5k ohm without the cap on the secondary and 8k ohms with the cap. All within spec.

CDI: no way for me to diagnose. I have tried two from ebay. One DC generic and another that stated it was DC, for the Dink, S9, Agility and so on - no dice.

I have no way to read if there is a signal from the CDI to the ignition coil. Would this be a readible voltage? Not sure if it is too fast to pick up.

I have tried a separate working battery from my lawn mower, and I have another ignition coil coming in, but I am still confused. I don’t want to just change parts in this situation. Also an OEM CDI is over 100$ plus dealing with a Kymco dealer and waiting on shipping.

I have tried other plugs as well, and ensured they, and my motor are grounded properly.

Do I need to look into the voltage regulator, rectifier or stator? I assumed as long as I had my 12.8V and my trigger signal (with an assumed working CDI) I would have spark.

Additionally, any recommendations for a CDI are appreciated. Any luck with Naraku?



Scootsuper9

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Re: 2T scooter - Ignition Help
« Reply #1 on: September 26, 2024, 01:59:30 PM »
Good news,

I figured out the issue and it 100% was my CDI. The EB the eBay CDI do work, but they have a different pin set arrangement. You can look up the typical DC CDI pinout I verified the orientation by by the two ground prongs using my ohm meter. I marked up a harness adjusted the plugs and I got spark.

I hope this helps out anybody facing issues getting a new CDI or having no spark because for some reason after all these years, it’s hard to find a resolution through the forms. I don’t know why Kymco Has their own proprietary arrangement maybe just to sell parts!

Hope I save someone a headache or some money!

Stig / Major Tom

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Re: 2T scooter - Ignition Help
« Reply #2 on: September 28, 2024, 01:55:19 AM »
Good work !
Thanks.

Stig
Boston Strong
Rural Ohio

And, I'm feeling a little peculiar.

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